Abstract
The chemistry of strained unsaturated cyclic compounds has experienced remarkable growth in recent years via the development of metal-free click reactions. Among these reactions, the cycloaddition of cyclopropenes and their analogues to orthoquinones has been established as a highly promising click reaction. The present work investigates the mechanism involved in the cycloaddition of strained dienes to orthoquinones and structural factors that would influence this reaction. For this purpose, we use B97D density functional theory calculations throughout, and for relevant cases, we use spin component-scaled MP2 calculations and single-point domain-based local pair natural orbital coupled cluster (DLPNO-CCSD(T)) calculations. The outcomes are analyzed in detail using the distortion/interaction model, and suggestions for future experimental work are made.